Dobbies for looms



July 5, 1955 F. DAVIES ETAL DOBBIES FOR LOOMS 6 Sheets-Sheet 1 FiledNOV. 6, 1952 ammo m 224% A TTOEA/fYIS July 5, 1955 F. DAVIES ET ALDOBBIES FOR LOOMS 6 Sheets-Sheet 2 Filed NOV. 6, 1952 11V VEYVTOESF/Lcwz m ATTOE/VEXIY July 5, 1955 F. DAVIES ET AL DOBBIES FOR LOOMS 6Sheets-Sheet 3 Filed Nov. 6, 1952 m mnthhhu Ha I L I I I July 5, 1955Filed 1952 DAVIES ET AL 2,712,32 DOBBIES FOR LOOMS 6 Sheets-Sheet 4/VVENTOES 1M I 24,

Filed Nov. 6, 1952 DAVIES ETAL DOBBIES FOR LOOMS 6 Sheets-Sheet 5 July5, 1955 F. DAVIES ET AL 2,712,327 DOBBIES FOR LOOMS Filed Nov. 6, 1952 6Sheets-Sheet 6 By J 7 F/r1/ KW 13% W, WQ M A TTOENEYJ Unite StatesPatent 055cc Z,7l2,327 Patented July 5, 1955 2,712,327 DOBBIES FOR LOOMSFrank Davies and John Kennedy Pitts, Didsbury, Manchester, England,assignors to The British Cotton Industry Research Association,Manchester, England, a British association Application November 6, 1952,Serial No. 319,044 14 Claims. .(Cl. 139-71) This invention relates todouble-lift open-shed dobbies for looms and is particularly but notexclusively applicable to positive knife dobbies.

It is usual for positive knife dobbies to have an oscillating baulkmoving in a vertical plane and the movealso movable In a vertical planeand pivoted to the ends of the baulks. The control of the hooks to bringthem into engagement or disengagement with the oscillating knives iseifected by feelers which in turn are under the mechanism to be located'inside' the dobby mechanism to provide the :interengaging necessary,'to enable the knives to :oscillate the baulks. Under certain conditionsfrom stops.

The object of the present :invention :is "to :provide 'an improved andsimplified construction of dobby mechto the pattern mechanism;

Fig. 3 is a part sectional end elevation on the line 3 3 Fig. 2.

Fig. 4 is a section on the line 4-4, Fig. 6, illustrating how thefeelers are controlled by the pattern chain.

Fig. 5 is a section on the line 5-5, 'Fig. 6, and showing warp shedclosed.

Fig. 6 is an end view of Fig. 5 looking from the right.

Fig. 7 is a detail view of the means illustrated in Figs. 5 and -6.

'In the drawings, and referring particularly to Fig. '1 thereof, thejack 10, ofwhich there are several according oted upper and lower hooks15, 16. The ends of the baulkare fashioned with bosses 12a and 12badapted to contact the back stops 13, 14 and also to be engaged by upperand lower knives or griffes 17, 18, as they move The upper hook 15 isalsofashioned with a downwardly and rearwardly projecting portion ortail 15d on the opposite side of pivot 15x from the hook portion 15a,

and abutting the upper face of said tail is the upper .the dobbymechanism. The inner or forward portion 15a of the hook 15 is heavierthan the tail portion 15d, so that the hook is loaded to tilt in aclockwise dithe baulk 12 is somewhat similar in'construction andoperation to the upper hook 1'5, and also has atcomparatively short,inner or forward portion 16a having a rabbet or notch 16b to engage thelower front stop 20,-and

hook 16 is also cut away at 16c to receive and engage the lower griffeor knife 18. In addition to the outer portion or tail 160?, the lowerhook has a weighted portion 16c, whereby it is caused to tilt on itspivot 16x in a counterclockwise direction to disengage from the lowerfront stop 20 and engage the knife 18 from underneath under the controlof bell-crank feeler 26 pivoted on shaft 26b. The upper end of thevertical limb of the bell-crank feeler 26 has a cam face 26a adapted tobe engaged by another peg of the pattern mechanism in manner similar tothe cam face 21a of the feeler 21 for the upper hook. The feelers 21 and26 are springloaded into engagement with the pegs of the patternmechanism, by a spring 27 extending between them forwardly of theirpivots 2.2 and 26b, respectively.

As illustrated in Figs. 2 and 3, the upper griffe or knife 17 extendsbetween and is flexibly mounted on the upper ends of a pair ofbell-crank levers 2b, 28a pivoted at 29, 29a the said levers beinglocated at each side of the machine with the knife 17 extendingtransversely across all the upper hooks. The proportions of thebell-crank levers and the location of the pivots thereof are so arrangedthat the knife can move angularly in an are substantially correspondingwith that followed by the pivots of the upper hooks when the baulks arerotated about the centres of the pivots of the lower hooks. The lowerknife or griife 18 is similarly supported or carried by a pair ofbellcrank levers 30, 30a pivoted at 31, 31:: but the bell-crank levers30, 30a are opposed with respect to the bell-cranks 28,. 28a, and links32, 32a connect the free ends of the bell-crank levers, so that if saidlevers are pivoted or moved angularly in a clock-wise direction, seeFig. 2, the upper knife 17 will move to the right while the lower knife18 will move to the left.

It will be understood that the angular path of movements of the lowerknife 18 substantially follows the arc of movement of the lower hooksduring pivoting movement of the baulks about the centres of the pivotsof the upper hooks.

in order to give the required angular movement to the bell-cranks, 28,28a, 3%, 30a and thereby oscillate the knives, the bell-crank levers areoscillated by cams. As shown in Fig. 2 for one side of the dobby, one ofthe arms of lever 30 is provided with a cam follower 33 rotatable on astud 33x, said cam follower being located in a cam groove 34, fashionedin a cam 35 mounted on a cam shaft 36. Thus it will be seen that leveris oscillated by cam 35 through cam follower 33 while the lever 28 isoscillated by the lever 30 through link 32. On the other side of themachine (see Fig. 3) the lever 28a is oscillated by a cam 35a mounted onshaft 36 and av cam follower 3311 while the lever 30a is oscillated bythe lever 28a through link 32a. The cam shaft is driven by a pair ofbevel gears 37, 38, see Fig. 3, the bevel gear 38 being mounted on adriving shaft 39 driven in turn from the loom top shaft (not shown). Thecam groove of each cam is so shaped that it will cause each griife orknife in turn to relieve all the adjacent hooks from their front end ofeach inward traverse, and in conwith the flexible mounting of the kniveswill also provide for the requisite slating or staggering of the knivesduring their osc'llating movement. For the latter purpose the cams areso shaped that one end of each knife is advanced relatively to the otherend, so that the knife moves forwardly in an inclined position, but ateach end of the stroke the knife occupies a noninclined position.

Also mounted on the cam shaft 36 is the driving member 40 of a Genevamotion, the driving pins thereof being identified by the numerals 41 and42. The driven member 43 of the Geneva motion is mounted on the patternbarrel shaft 44 and by the driving connection illustrated in Figs. 2 and3 the knives 17, 18 are oscillated in timed relationship with thepattern control mechanism.

- on which the warps are located.

It is usual to operate several jacks by the dobby mechanism and eachjack has its own baulk with upper and lower hooks. The cam grooves 34oscillate the knives 17, 18 in known manner and the hooks 15 and 16pivot into or out of engagement with their respective knives undercontrol of the pivoted feelers (see Fig. 4), to operate the jacks 10 inmanner required to weave The cam grooves 34 are so proportioned andshaped that the knives on the backward movement of their traverse,engage the bosses 12a, 12b, at each end of each baulk to move same asufiicient distance to relieve the hooks from the front stops 19, 20whereupon free pivotal movement of the hooks can occur, by reason oftheir unbalanced construction, it allowed to do so by the feelers 21,26. If a hook is prevented by the pattern chain (operating through thefeelers) from engagement with its associated knife, then on outwardmovement of said knife the hook rests against the front stop.

It will be appreciated from the showing of Fig. 1 that the weighting orloading of the bottom hooks at their tail or rearward portions urgesthem to pivot to engage the lower knife 18 from underneath.

As is well known in the textile trade it is desirable when weavingartificial silk to close theshed and equalize the tension on the warpthreads if and when the loom is stopped for any length of time, forexample over-night, in order to prevent stretching of the said threads.

In the improved dobby construction, provision is made for closing theshed and reference is now made to Figs. 5, 6 and 7, wherein isillustrated means therefor. Said means comprises an upper rod 45extending above and transversely of all the tails 15d of the upperhooks, and a lower rod 46 above and extending transversely of all thefeelers 26, and said rods are supported by and between the upper andlower ends of a pair of bell-crank levers 47, 47 mounted on shaft 22journalled in bearings 49, 49. In order to give the requisite pivotalmovement to the shaft 22 to lower the upper rod 45 into contact with thetails of all the upper hooks to disengage them from the upper knife 17and engage them with the upper front stop 19, an operating handle 50 isprovided pivoted at 51, and at one end of said lever is an arcuate slot52 in which is located a pin 53 fixed to the upper end of asubstantially vertical arm 54 on the shaft 22. It will be appreciatedthat when the handle 50 is moved to the position indicated in dot-dashlines in Fig. 7, the pin 53 will be moved to the dotted position (Figs.5 and 7), and consequently a partial angular movement will be impartedto the shaft 22 through the arm 54, and such movement will pivot thebell-crank levers 47 and cause the rod 45 to make contact with all thetails of the upper hooks and pivot them out of contact with the upperknife or gritfe, thereby relieving simultaneously all the upper hooksand holding same free from engagement with the upper knife. Similarlyand simultaneously the lower rod 46 is engaged with the lower feelers 26and moves them to the dotted position, Fig. 5, allowing the bottom hooks16 to rise for engagement with the lower knife 18.

It will be understood from the foregoing description that, as used inthe specification and claims hereof, the terms front, forward andforwardly have reference to that side of the dobby mechanism on whichthe warps are located, while back, backward, backwardly" and rearwardlyhave reference to the side opposite that What we claim is:

1. A double lift open-shed dobby for looms comprising a plurality ofbaulks each having an upper hook and a lower hook pivotally mounted onthe upper and lower ends, respectively, of the baulk, upper and lowerfront stops adjacent the respective ends of the baulk for preventingforward movement of the hooks and of the associated supporting ends ofsaid baulk s, a pair of upper and lower oscillatory knives positionedforwardly of said stop engaging portion extending forwardly, and a tailportion extending rearwardly, of its pivot, pivotally 2. A double liftopen-shed dobby according to claim 1 wherein the knife engaging portionsof said hooks are relatively short and have notches formed therein forengagement with said front stops.

3. A double lift open-shed dobby according to claim 2 wherein the weightof each hook is so distributed relagagement with said feeler members.

4. A double lift open-shed dobby for looms comprising any desiredposition.

A double lift open-shed dobby according to claim 8 e 9. wher in s bers,respectively.

aid hook raising and feeler member moving 10. double lift open-sheddobby according to claim 1 tions and shedding is progressive across theloom.

12. A double lift open-shed dobby according to claim 11 wherein the cammechanisms at the opposite ends of the knives References Cited in thefile of this patent UNITED STATES PATENTS Goodyear July 1,

Heatley et al. July 15,

Wiget June 29,

Wiget Nov. 25,

FOREIGN PATENTS Great Britain Feb. 10,

Great Britain Jan. 29,

